Electrical discharge device



Jan. 25, 1949- H. DEB. KNIGHT ELECTRICAL DISCHARGE DEVICE Filed Sept. 25,1946

z Inventor: 22 s Hen de Bogne Kn ht,

23 b y j gj k 14 His Att owne s.

Patented Jan. 25, 1949 attain 2,460,132 ELECTRICAL DISCHARGE DEVICE Henry dc Boyne Knight, Rugby, England; assignor to General Electric Company,

or" New York' a corporation Application September 25, 1946,.Serial No. 699,205 In Great Britain- November. 10,1943

aw 690, August-18', 1946 November 10, 19633 14 Claims. (Cl. 250-275) Section Public L Patent expires The present inventionrelates to electric discharge. devicesand in particular to the manulactureof. such. devices. in. which the evacuated or gas-filled envelope is of simplified construction conveniently adaptable to. economical. quantity manufacture: and. which may consist. wholly. or mainly of ceramic or similar insulating materiali It. is. essential. in manufacturing electric dis.- charge: devices tomaintain. a. predetermined relationship between the electrodes of the device, and it:is one.of the main objects of the present. invention to provide a construction for devices employing a ceramic envelope in which the required disposition of the electrodes and the securing of the electrodes in position in the en:- velope can readily be effected.

An. electric discharge device according to one aspect-oi the invention comprises an. envelope or ceramic'material within which an electrode is securedby meansof a closure plate or header which covers an opening in and is sealed to the envel'ope, the-interior periphery of the envelope or the header being provided with an annular shoulder against which-the electrode or a-suppor-t therefor abuts,- whereby the electrode is both-positioned within the envelope and secured thereto by-thesealing' of the header to the envelope.

According to another aspect of the invention, an electric discharge device comprises an envelope of ceramic material within which an rode is secured by means of a shoulder which covers arr-opening in and issealed to the envelope; the electrode, or a support therefor, being provided with a peripheral shoulder which abuts preferably efiectedby glass.

elecagainst the inner periphery of the envelope and with an outwardly extending seal-ed between the header and the rim of the envelope.

In carrying out the invention. in connection with a discharge device possessing two electrodes between which a discharge is adapted to occur when" a' predetermined potential between them is exceeded, the device thus being of the nature of a spark gap, while one electrode is secured to the envelope by means of the header, as above set forth, the other electrode may be accurately spaced with respect to the first electrode by mounting it at the end of the envelope remote from the header by'means of a support'rod sealed through an opening in the envelope. This second electrode may have its rim seated against an internalshoulderin the inner periphery of the wall of the envelope so as to space it accurately from the other" electrode.

flange which is cathode may then comprise wscaledetherethrough.

A somewhat similar construction: may be employedfor again.- provided, one of them consisting of an electron-emitting cathode; Thesupport for the a member sealed between the header and the envelope in the mannerabovedescribed, this support constituting one terminal oie the cathode wh'le the other terminal isbrought through:anapertureinthe header and or more sections;, each section having one "terminal. connected to the support? sealed; to the envelopeby the header;v while; a common terminal for each: section is connected to the second. lead which is. independently brought through the header. The: cathode may beiof the indirectly heated type, if desired; in which case the indirectly heated portion may consist of a hollow cylinder mounted onor forming part of the support for. the" cathode-which issealed to the envelope and; the header;

Th'ehea'der preferably" consists also of ceramic material but it may consist of metal. In the case in whi cli theheader consists of metal, any leads required to be brough through insulating relation thereto may be brought through by glass to-metal seals of-well'k nown character.

The sealing of the header tothe envelope is Theglass may be providedin the neighborhood of the seal in the form ofa collar constituted by a short length of glass tubing, the glass being softened and caused to flow toform' the seal by heating thedevice, preferably in a reducing atmosphere, after assembly.

When glass is employed for sealing, it is necessary toensure that the thermal expansion coefiicient of the glass is suitably matched to that of the ceramic material and to any metal which may be present at the seal.

Alternatively, the sealing may be effected by soft solder, in which case those parts whereat sealing, is to be eifected and which consist of ceramic material arepreviously provided. with an adherent metallic coating, for example, by coatingwith an oxide of tungsten or molybdenum, as hysputtering, andreducing the oxideto a metal.

in the case in which two or more electrodes are to be secured in the envelope in spaced" relationship to one another by means of the header, each electrode or'the'supp'ort therefor may be provided,

with a peripheral flange which fits within a shouldered recess in the interior wall of the en.- velope adjacent the open end thereof, one of the flangesbe'ing' seated against the shoulder, while the-casein which two electrodes are The cathode maybe in twoanother (or others) is seated against an insulating ring which separates electrically two otherwise adjacent flanges. The flanges are then secured in position within the recess by seating against the outermost flange (or an insulating ring placed thereon) a header which closes the open end of the envelope and is sealed thereto.

Conveniently, the envelope may consist of a cup-shaped hollow body of ceramic material, but a hollow cylinder may also be employed. In the latter case electrodes may be secured to both ends of the envelope by the means above set forth. When the envelope is cup-shaped, the closed end thereof may be provided with an aperture through which the lead to an electrode supported at the closed end of the envelope is brought. A shoulder may be provided adjacent the closed end of the envelope for seating the electrode thereagainst if desired.

In the case in which the envelope is completed by sealing a single header to an open end thereof, the remote closed end may be provided with an opening through which the evacuation and, if desired gas filling may take place.

The invention will now be described with the aid of the accompanying drawings, in which Figs. 1, 2 and 3 show in cross-section illustrative alternative methods of locating an electrode with respect to a ceramic envelope by means of a header which is sealed to the envelope; Fig. 4 illustrates in cross-section a hermetically sealed spark gap constructed in accordance with the invention Fig. 5 a method of providing a sealing- 01f tubulation for the envelope; and Figs. 6, 7, and 8 alternative constructions for a multi-electrode discharge device in accordance with the invention. In the drawings, like numerals have been used to designate like parts throughout.

Referring first to Figs. 1, 2 and 3, there is shown therein methods of employing a ceramic header for locating and sealing an electrode into a ceramic envelope. The header I is fitted to a generally cylindrical ceramic envelope 2 and is sealed to it by the glass shown at 3, thereby forming a closure for the otherwise open end. The electrode 4, which may be made in the form of a pressed metal disk, is provided with a peripheral shoulder 5, which abuts against the internal periphery of the envelope 2, and an outwardly flanged portion 6 resting against the end of the envelope between the header I and the envelope rim. The sealing of the header to the envelope by glass thus secures the electrode in position in desired relationship to the envelope. The header may be provided with an aperture 1 through which a leading-in wire to the electrode may be passed and sealed therein in any suitable manner, e. g., by glass in a manner similar to that shown in Fig. 4. In the arrangements shown in Figs. 2 and 3 the header is provided with an internal shoulder 8 to receive the rim of the electrode flange. 7

In Fig. 2 the shoulder 5 serves to center the electrode and the header with respect to the envelope,.while in Fig. 3 the flange on the electrode abuts against the shoulder 8 so that the positioning of the header on the envelope efiects the centering of the electrode therein.

Referring now to Fig. 4, which illustrates an exemplary construction of a spark gap, the envelope 2 is made cup-shaped and is provided adjacent its open end with an annular shoulder 9 against which the flanged portion 6 of the'electrode 4 rests. The header I is made to fit into the recess in the open end of the envelope and is again sealed thereto by glass as at 3. II desired the glass may be arranged to extend over the whole external surface of the header, as indicated in interrupted lines. In this construction, the second electrode III of the spark gap is seated against an internal shoulder II adjacent the closed end of the envelope, and the leading-in conductor I2 to electrode I0 is brought through an aperture in the closed end of the envelope and is sealed therein by glass as at I3.

With such a construction the electrodes 4 and III may be accurately spaced, in so far as the electrodes are made from stampings and are thus of constant dimensions and since the spacing of the shoulders 9 and II of the envelope can be accurately controlled. If desired, the electrode III may be mounted in a similar manner to that adopted for the electrode 4- by making the envelope in the form of a hollow cylinder open at both ends and seating the electrode I0 against a shoulder similar to the shoulder 9 but adjacent the remote end of the tube. The closure of the remote end is then effected by a header similar to I.

In Fig. 5 there is illustrated the manner in which evacuation of the envelope may be effected by providing a boss I I on the header I and surrounding the boss by a glass tube I5 which is sealed around the boss. The glass tube I5 may then be connected to a Vacuum pump and sealed in the usual manner when the device has been evacuated and/or gas-filled.

In place of providing an internal shoulder within the envelope we may employ a series of internal projections which form a discontinuous shoulder and which are to be regarded as being equivalent to the shoulder.

Referring now to Fig. 6 there is shown a construction of a three-electrode discharge device embodying the invention. The cup-shaped envelope 2 is again provided with an internal shoulder 9 adjacent its open end against which the rim of a control electrode I5, or support therefor I6, is seated, the electrode I5 being held in position by sealing-in the header I in the manner above described. In this case the cathode I1 is in the form of a directly heated filament having leads or supporting rods I8 passed through apertures in the header I which are sealed by glass. A lead I9 may be connected to the support for the control electrode I5 and passed through a notch or groove in the periphery of the header I prior to the sealing of the header to the envelope by the glass shown at 3. The electrode I5 and its support I6 may be of suit able cylindrical construction. The anode 20 is supported from the closed and of the envelope by means similar to that already described in connection with Fig. 4.

Fig. 7 shows a further construction similar to Fig. 6 in which two or more electrodes may be supported from the end of the envelope closed by the header I. In this case, the support for the control electrode I5 is seated against the shoulder 9, and against the flange portion of the support is placed an insulating ring or disk 2| having apertures for the passage of the leadingin wires to the cathode II. As indicated at 22, these lead-in wires are then spread out around the edge of the header I, which is sealed to the envelope by glass at 3, and holds the electrodes in position. The leads 23 to the cathode and 24 to the grid are peripherally spaced from one another to provide adequate insulation, the leads being taken through notches in'the periphery of am new theheader as describedin connection with Fig. a

thearrangement shown Fig. '1 the mode 20 is supported by means of afurther header sealed tothe-envelopeby glass. The anode 29 may be supported and centered within the envelope by any of the methods shownin- Figs. 1, 2, 3', or 4- if desired.

Where an indirectly-heated type of cathode is required; a cathode cylinder surrounding a heater element. simi-iar to cathode-I1 may be provided a. flanged support on its lower end which is hcld'betwe'en the" header l and an insulating ring 2t, the heater leads being taken through the header as in Fig. (i. Where a lead to another eiectro'de is to pass a conducting flange, the flange maybe providedwith a cut away portion. to avoid electrical connection between. the electrodes. Such an arrangement ls-shown in Fig. 8 wherein the support It for the grid; [5. is positioned bythedisk 2| as in Fig. T; while a cathode cylinder 25 (which may provided with at thermionically emissive coating) is arranged to: fit concentricatly' within a circular hole in the center of disk Z-l. A flange cathode cylinderLZS is arranged to engage a recess in the lower wall of disk 2t. As in Fig. the header I is sealed to the envelope and holds both disk. 2t and thee'l'ectrodes in position. The cathode-heater t1 may be provided with leads .23 extending through the header Lead to the grid t5 may be provided as before andxalead 2.! to the cathode 25 may be arranged to pass through the:- lassse'al and inbetween the 21 and; header I to contact the flange, 26. It will be understood or. course: structuresuch as in Fig. '7' maybe provided,

While Ihave shown and described a particular ernhomrnent. of my invention, it willbe obvious to. those: skilledin; the art that various changes and modifications may be made without departing from my invention its: broader aspects and I, therefore, aim the appended claims to cover all such changesaand modifications as fall. within the true spirit and scope of my invention.

WhatI claim as new and desire to secure by Letters Patent is:

1. An electric discharge device comprising a plurality of electrodes, an hermetically sealed envelope for said electrodes including a portion defining a part of a closed discharge chamber and having an openingtherein, a closure member hermetically sealed to said portion and covering said opening, and a shoulder adjacent the juncture of said portion and said closure member, one of said electrodes having a portion secured between saidportion of said envelope. and said closure member in engagement electrode is supportedirom and positioned within said envelope.

2. An electric discharge device comprising a plurality of electrodes, an hermetically sealed envelope for said'electrodes including a. substantially cylindrical portion defining a part of a. closeddischarge chamber and having an open end therein, a closure member hermetically sealed to said: portion and covering'said' opening, and a. shoulder adjacent the juncture of said portion-and said closure member, one of said 'electrodes having a flanged'pcrtion secured between said portion of saidenvelope and said closure member in engagementwith said shoulder whereby said electrode is supported'from and positioned within said envelope.

3. An electric discharge device comprising a plurality of electrodes, an hermetically sealed envelope for said electrodes including a portion 2a on the lower end ofithe I as in Fig. 6..

that an anode with said shoulder whereby said over saidopening, one

1 portion secured.

defining apartcr a closed discharge-chamber and and a closure member hermetically sealed to sa'diporti'on and: covering having an opening thereim said opening; said. portion. having a shoulder thereon. adjacent the jnncture of said-portion and said closure: member, one: or said. electrodes hav mg: a portion secured between said: portion or said envelope andsaidiclosurememher in engagemerit said shoulder whereby said electrode is supported: from. and positioned within saidenvelope;

41. An; electric discharge device comprising a plurality or electrodes, an hermetically sealed enyelepeior said elect odes including a substantially: cylnidricat portion defining a part of: a closed. discharge. chamber and having. an: opening therein, and a closure member hermetically sealedto said portion saidoportion having a shoulder thereon adjacent the juncture. oil said. portion. and. said closurenrenrber, one oi'said' electrodes having. a flanged portion secured. between said-portion of said envelope and said closure member in engagement in said shoulder whaeby" saideiectrod'e is supported. from and-positioned within said envelope:.

5:, An cl'ectric d-isohargedevi'ce comprising aplnrality of electrodes, arr hermetically sealed envelope tor "id ci ct odes including aportion. defining-a part.- of a;closed.discharge chamber. and

having" an openingtherein, atfirst' closure memher in engagement with saidpcrtion and: covering said opening, and a second closure memb'er'hermetinal'ly sealed to. said. portion over said. first closure member forming an. hermetic seal of. said electrodes having a. portion secured. between said. envelope and saidfirst cicsure member whereby said electrode is supported from and positioned. withinsa'id envelope-,- another of. said. electrodes having a. portion. secured between. said: first and. second closure. members extending, through said: first closure member into said discharge chamber whereby said. other electrode is supported: and positioned: within said envelope.-

6. electricdischarge device: comprising. a plurality oielectrodes; an hernia ioally sealedenvelop'e for said electrodes. including a. substantially cylindrical portion; defining a part of. a; closed. discharge: chamber and. having an open end. therein, a. disk. shaped-imember" in engage ment with said portion and'covering said opening;. and closure member hermetically sealedto said over said disk. shapednmember and forming an hermetic seal over said opening, one of said electrodes having aflanged portion secured between. said. portion: of saidenyelope and saiddislr. shaped member supported from; an positioned within said envclope, another of said. electrodes havinga flanged. between said. di'sle shaped. and closure members and extending through said shaped member into said discharge chamberwhereby said other electrode is supported andv positionedwithinsaid'envelope.

'7. an. electric discharge device comprising a plurality of electrodes, an hermetically-sealed. envciope for. said-electrodes including a. portion de fining a. part. of a closed. discharge" chamber and having an opening therein, a .firstclosure member in. engagement with. said portionand covering said opening, a second'closure member hermetically sealed to said'portionover said first closure and covering: said opening,

portion. of said whereby said. electrode. is

said electrodes having a portion secured between said portion of said envelope and said first closure member in engagement with said shoulder whereby said electrode is supported from and positioned within said envelope, another of said electrodes having a portion secured between said first and second closure members and extending through said first closure member into said discharge chamber whereby said other electrode is supported and positioned within said envelope.

8. An electric discharge device comprising a phu'ality of electrodes, an hermetically sealed envelope for said electrodes including a generally cylindrical portion defining a part of a closed discharge chamber and having an opening therein, a disk shaped member in engagement with said portion and covering said opening, a closure member hermetically sealed to said portion over said disk shaped member and forming an hermetic seal over said opening; and a shoulder adjacent the juncture of said portion and said disk shaped member, one of said electrodes having a flanged portion secured between said portion of said envelope and said disk shaped member in engagement with said shoulder whereby said electrode is supported from and positioned within said envelope, another of said electrodes having a portion secured between said disk shaped and closure members and extending through said disk shaped member into said discharge chamber whereby said other electrode is supportedand positioned with said envelope.

9. An electric discharge device comprising a plurality of electrodes, an hermetically sealed envelope for said electrodes including a portion defining a part of a closed discharge chamber and having an opening therein, a first closure member in engagement with said portion and covering said opening, and a second closure member hermetically sealed to said portion over said first closure member and forming an hermetic seal over said opening, said portion having adjacent said opening a shoulder thereon upon which said first and second closure members rest, one of said electrodes having a portion secured on said shoulder between'said portion of said envelope and said first closure -member whereby said electrode is supported from and positioned within said envelope, another of said electrodes having a portion secured between said first and second closure members and extending through said first closure member into said discharge chamber whereby said other electrode is supported and positioned within said envelope.

10. An electric discharge device comprising a plurality of electrodes, an hermetically sealed envelope for said electrodes including a substantially cylindrical portion defining a part of a closed discharge chamber and having an open end therein; a disk shaped member in engagement with said portion and covering said opening, and a closure member hermetically sealed to said portion over saidfirst closure member and forming an hermetic seal over said opening, said portion having adjacent said opening'a peripheral shoulder thereon upon which said disk shaped and closure members rest, one of said electrodes having a flanged portion secured on said shoulder between said portion of said envelope and said disk shaped member whereby said electrode is supported from and positioned within said envelope, another of said electrodes having a- Si flanged portion secured between said disk shaped and closure members and extending through said first closure member into said discharge chamber whereby. said other electrode is supported and positioned within said envelop v 11. An electric discharge device comprising a plurality of electrodes, an hermetically sealed envelope for said electrodes including a substantially cylindrical portion defining a part of a closed discharge chamber and having an opening at one end thereof, a closure member hermetically sealed to said portion and covering said opening, and a peripheral shoulder at the other end thereof, one of said electrodes having a portion secured between said portion of said envelope and said closure member whereby said electrode is supported from and positioned within said envelope, another of said electrodes being supported on' said peripheral shoulder.

12. An electric discharge device comprising a plurality 0f electrodes, an hermetically sealed envelope for said electrodes including a substantially cylindrical portion defining a part of a closed discharge chamber and having an opening at one end thereof, a first peripheral shoulder adjacent said opening, a closure member engaging said shoulder hermetically sealed to said portion and covering said opening, and a second peripheral shoulder-at'the other end thereof, one of said electrodes having a flanged portion'secured between said portion of said envelope and said closure member whereby said electrode is supported from and positioned within said envelope, another of said electrodes being supported on said second peripheral shoulder.

13. An electric discharge device comprising a plurality of electrodes, an hermetically sealed envelope for said electrodes including an envelope member defining a part of a closed discharge chamber having an opening therein, and a closure member hermetically sealed to said envelope member and covering said opening, a peripheral shoulder on one of said members adjacent the juncture of said members, one of said electrodes having a portion secured between said members and engaging said shoulder to position said electrode wi thin said envelope.

14, In an electric discharge device, the combination comprising a hermetically sealed envelope including a cylindrical member having an opening and a closure member sealed to the open end of said cylindrical member, an electrode supported within said envelope and including a flanged portion received between said cylindrical member and said closure member, said electrode and said envelope havingaxially extending interengaging surfaces in the region of the juncture of said members cooperating to position said electrode wtihin said envelope.

HENRY or: BOYNE KNIGHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,034,433 Heintz Mar. 17, 1936 2,164,910 Goebel et al. July 4, 1939 2,303,166; Laico N0v.'24, 1942 2,308,800

Anderson; Jan. 19, 1943 

